The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 05, 2007
Filed:
Nov. 05, 2004
Sagheer Ahmad, Sunnyvale, CA (US);
Lin Chen, Cupertino, CA (US);
Sam Huynh, Mountain View, CA (US);
Shu-shia Chow, Los Altos, CA (US);
Joe Macri, San Francisco, CA (US);
Sagheer Ahmad, Sunnyvale, CA (US);
Lin Chen, Cupertino, CA (US);
Sam Huynh, Mountain View, CA (US);
Shu-Shia Chow, Los Altos, CA (US);
Joe Macri, San Francisco, CA (US);
ATI Technologies Inc., Markham, Ontario, CA;
Abstract
An impedance compensation circuit generates per-group pull-up impedance information and per-group pull-down impedance information to calibrate a plurality of input/output pads and dynamically updates impedance information on a per channel basis. A group refers to a group of I/O pads having similar output drive strengths in a channel. A channel refers to all I/O pads, which collectively provide a bus interface to an external device. For example, all the I/O pads interfacing with a memory module may be grouped into a channel, and address I/O pads in a channel may be arranged into a 'group.' Memory I/O pads may be grouped together into a channel since memory interface pads have input/output characteristics that may be different from those of other types of I/O pads in the chip. According to one embodiment, per-group programmable offset information provides calibration information that may be different for each group in each channel.